unknown component

[Geo]

i have what to some of you may be a very noobish question.i have some components that many years ago i was selling to a man for what i thought was a good price of $1.00 a pound and he called them parakeets.they range in size from 1 centimeter to as large as 15 centimeters and are shaped like an egg with two legs,they also range in color orange blue green black .i dont have photos but i have a part number from a rather large one that i cant seem to find on the net, K68 on top and +25V under that.if anyone knows what these are would you please post for me and let me know what they contain.also there were some that were in a silver canisters that you couldnt crush with pliers or cutters.thanks in advance.

 

[qst42know]

See if this is what you were thinking of.

http://www.google.com/images?um=1&hl=en&rlz=1T4ADBF_enUS241US242&tbm=isch&sa=X&ei=kBCiTbXaEo6ztwelosmBAw&ved=0CDYQvwUoAQ&q=tantalum+capacitors&spell=1&biw=1131&bih=631

 

[Geo]

thank you for replying, im unsure,it looks alot like that but i didnt see anything that was an exact match.i will break some down and dissolve in hydrochloric acid and see what drops out.i will follow the PM videos and do a stannous test to check for PM's.i was hoping for a definite ID before wasting time and chemicals.

 

[qst42know]

Here is the color code for multi color ones I have seen some of. Most I see now are numbered instead.

http://www.marvac.com/fun/tantalum_capacitor_codes.aspx

 

[qst42know]

I have read Tantalum has the acid resistance of glass. Being only attacked by hydrofluoric acid.

The cylindrical type is known to have a silver content so nitric would be a better choice.

http://technology-electronic.blogspot.com/2010/06/tantalum-electrolytic-capacitors.html

 

[machiavelli976]

thank you for replying, im unsure,it looks alot like that but i didnt see anything that was an exact match.i will break some down and dissolve in hydrochloric acid and see what drops out.i will follow the PM videos and do a stannous test to check for PM's.i was hoping for a definite ID before wasting time and chemicals.

You may try a digestion in 50% NaOH . Tantalum oxide has a strong acid character , therefore is chemically inert to all the acids except HF. Not even AquaRegia can penetrate it.